Woodwind musical instruments, e.g., saxophones and clarinets, and other devices such as bird calls, utilize the vibration of a reed in response to a flow of air to generate a tone. These reeds include natural cane reeds and synthetic reeds. Tone generation in general depends on proper reed vibration. The reed is typically placed in contact with a mouthpiece to cover an opening or window. The reed is held in place by an adjustable clamp or ligature that surrounds the mouthpiece and the reed. Variations in the mouthpiece and ligature affect the vibration of the reed and, therefore, the performance or tone of the device or instrument.
The essential function of the mouthpiece of a woodwind instrument is to provide support for the reed over an aperture that allows the reed to vibrate and to direct the energy from the reed vibration through the aperture and into the bore of the instrument. The function and performance of a mouthpiece is influenced by the arrangement and geometry of the facing around the aperture as well as tone chamber below the reed which defines the route from the aperture to the bore. The facing is conventionally a flat surface on the mouthpiece surrounding the aperture, and the reed is placed in contact with this flat surface, covering the aperture. The facing includes the aperture, called a window, and the window is surrounded by a table on one end, two side rails extending from the table and a tip rail opposite the table. The reed functions as a reed valve during vibration, opening and closing the window.
A clarinet also includes a separate tuning barrel connected to the clarinet mouthpiece. The clarinet mouthpiece and the clarinet barrel are important components of the clarinet and contribute to the intonation, response, tone color and evenness of the clarinet. Typically, there is a distinct and very noticeable difference in tonality of the upper and lower registers of a clarinet. The very lowest register has a big-bodied tone; however, as the notes being played progress into the upper register, the tone loses its body and dimension, becoming relatively thin. As times, the tone can sound shrill. This effect is the result of the disparity in the cavity dimensions of the mouthpiece with respect to that of the relatively large bore of the instrument. When the lower notes are being played, the length of the oscillating air column is such that the generated tone is largely that which is developed in the bore of the instrument. When the higher notes are sounded, the tonality becomes more influenced by the cavity dimensions of the mouthpiece, which are relatively small in comparison to the cavity dimensions of the bore of the instrument. In regard to the lack of clarity of the throat tones, this is due to the fact that the transverse air column vibrations are not harmonically related to the longitudinal vibrations. Therefore, there is little harmonic cooperation. This condition exists in all wind instruments. Certain notes sound more clear than others in all instruments.